Lawnmower



y 21, 1970 H. EMMERICH 3,521,434

LAWNMOWER Filed Oct. .4, 1967 4 Sheets-Sheet 1 INVENTOR; 'i -iwgfl CmATTORNEY v y 1970 H. EMMERICH 3,521,434

' LAWNMOWER Filed Oct. 4, 1967 4 Sheets-Sheet 2 III H. EIMMERICHLAWNMOWER 4 Sheets-Sheet 5 Filed Oct. 4, 1967 w w? v w um Mm .x w 1W wmqq l mm on 8 mm 3 mm w mm mm v -N Pm m July 21, 1970 H. EMMERICH3,521,434

LAWNMOWER I Filed 001;. 4, 1967 4 Sheets-Sheet 4 United States PatentInt. (:1. Mid 35/26 I as. Cl. 5625.4 17 Claims ABSTRACT OF THEDISCLOSURE A lawnmower whose housing consists of cast aluminum ormagnesium alloy. The crank case, exhaust d-uct, fuel tank, carburetor,filter space and passages for cooling air, fuel and combustion productsare integral with or are defined by a one-piece casting whichconstitutes the housing and is mounted on wheels. The cylinder of thetwostroke cycle engine is inserted into the housing in horizontalposition and drives a vertical crankshaft which carries a blade and animpeller wheel serving to circulate cooling air, to support a magnet ofthe ignition system, and to transmit motion to the crankshaft duringstarting. A grass evacuating duct surrounds the engine, and the impellerwheel seals the underside of the housing. The upper side of the housingis closed by a detachable platelike cover.

BACKGROUND OF THE INVENTION The present invention relates to lawnmowersof the type wherein the blade rotates about a vertical axis. Moreparticularly, the invention relates to improvements in power-operatedlawnmowers.

It is already known to make the housing of a lawnmower of an aluminum ormagnesium alloy. Such housings are preferred over housings consisting ofdrawn sheet steel stock because they are more resistant to corrosion,less likely to produce excessive noise, lighter and of eyepleasingappearance. However, presently known light metal housings are quiteexpensive and their manufacture necessitates the use of a large numberof dies.

SUMMARY OF THE INVENTION It is an object of my invention to provide asimple, compact and inexpensive housing or chassis for a poweroperatedlawnmower.

Another object of the invention is to provide a lawnmower whichcomprises fewer parts than a conventional lawnmower and which can beassembled, dismantled, cleaned, inspected and/or repaired with littleloss in time.

A further object of the invention is to provide an improved housing fora lawnmower of the type wherein the blade rotates about a vertical axisand is driven by an internal combustion engine.

An additional object of the invention is to provide a lawnmower whereinseveral components of the internal combustion engine form an integralpart of the housing.

A concomitant object of the invention is to provide a lawnmower whereinthe fuel tank and the crankcase form integral parts of the housing.

Briefly outlined, my invention is embodied in a lawnmower comprising awheel-mounted housing consisting of a one-piece metallic casting, rotaryblade means, and an air-cooled internal combustion engine having arotary output member connected with the blade means. The engine furthercomprises a plurality of components which constitute integral parts ofand/or recesses, channels, ducts, passages or like cavities provided inthe one-piece housing. Such components include a fuel tank, an exhaustduct for combustion products, a compartment for a portion 3,521,434Patented July 21, 1970 of a removable cylinder which drives the outputmember, a crank case for the output member, a carburetor, and a casingwhich defines a path for the flow of cooling air to the cylinder andaround other heat-sensitive components.

The output member further carries an impeller wheel which circulates airand is in sealing engagement with the underside of the housing justabove the blade means. A flat plate-like cover is detachably secured tothe upper side of the housing and overlies the fuel tank, crank case,exhaust duct and one or more further components of the engine.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved lawnmower itself, howover, both as to its construction and itsmode of operation, together with additional features and advantagesthereof, will be best understood upon perusal of the following detaileddescription of a specific embodiment with reference to the accompanyingdrawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an exploded perspective viewof a lawnmower which embodies my invention;

FIG. 2 is a top plan view of the lawnmower with the cover removed andwith the cylinder shown in section;

FIG. 3 is a longitudinal vertical section as seen in the direction ofarrows from the line III-III of FIG. 2; and

FIG. 4 is a transverse vertical section as seen in the direction ofarrows from the line IVIV of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The improved lawnmower comprisesa housing 1 provided with an arcuate grass evacuating channel 2 andmounted on four wheels 3'. The channel 2 surrounds a substantiallycircular central part of the housing 1 (see particularly FIG. 2) whichaccommodates a two-stroke cycle internal combustion engine. Severalcomponents of the engine are integral with the central part of thehousing 1 and include a crank case 4, a fuel tank 5, a cylindercompartment 6 and an. air circulating compartment 7. The cylinder isshown at 8 and the space for the air cleaner or filter 50 is denoted bythe numeral 9.

The housing 1 is provided with a depression or groove which extendsbetween the crank case 4 and fuel tank 5. This groove has a first part10* which is the carburetor and a second part 11 which is the feed ductfor admission of a combustible mixture into the cylinder 8. The fueltank 5 is located opposite an exhaust duct 12 which is separated fromthe crank case 4 by a heat-insulating air gap 13. The cylindercompartment 6 is connected with the exhaust duct 12 by a passage 14.

In the region below the fuel tank 5, the housing 1 defines a helicalcasing 15 for the engine cooler. This casing 15 communicates with theair circulating compartment 7. The housing 1 further comprises mountingmeans 16, 17 for an ignition coil or interrupter. All of the heretoforedescribed components 2, 47 and 9-17 form integral parts of or aredefined by the housing 1. This housing is a one-piece casting whichpreferably consists of a lightweight and corrosion-resistant aluminum ormagnesium alloy.

The housing 1 supports a detachable cover or shroud 18 which issubstantially flat and has an opening 19 for admission of fuel into thetank 5. The cover 18 is further provided with slits 20 located above thegap 13 to admit fresh air. Still further, the cover 18 has a recess '9which forms an extension of the space 9 for the filter 50 and a recess6' which forms an extension of the cylinder compartment 6. Portions orwebs 21 of the cover 18 are in sealing engagement with the adjoiningportion of the housing 1. An overflow channel 22 is provided above therecess 6'.

The cylinder 8 is inserted into the air circulating compartment 7 and italso extends into the compartment 6 and extension 6'. This cylindercomprises a smoothsurfaced cylindrical portion 25 which fits into thecomposite compartment 6, 6. The cylindrical portion 25 has fueladmitting ports 23 in communication with the feed duct 11 and exhaustports 24 in communication with the passage 14. A flange 26 of thecylinder '8 is bolted to the housing 1. The cooling fins 27 of thecylinder 8 are accommodated in the air circulating compartment 7. Theupper side of the compartment 7 is open.

The housing 1 is further provided with a vertical bearing sleeve 28which extends downwardly from the crank case 4 and accommodates aportion of a crankshaft 29 which constitutes the output member of theengine. The upper end of the crankshaft 29 extends into the crank case 4and carries a crank arm 30 coupled to the piston 32 of cylinder 8 by apiston rod 31. The lower end of the crankshaft 29 carries a bladedimpeller wheel 33 which is surrounded by the channel 2 and closes themedian portion of the underside of the housing 1. The marginal portion34 of the impeller wheel 33 forms with the housing 1 a labyrinth seal 35which is shown in FIG. 4 and serves to prevent entry of grass into thepath wherein cooling air circulates when the impeller wheel is driven bythe crankshaft 29. The magnet 36 of the igniter assembly is cast intothe body of the impeller wheel 33 (see FIG. 1). The underside 37 of theimpeller wheel 33 is adjacent to a blade 38 which is affixed to thecrankshaft 29 and is provided with cutters 39. The cutters 39 severgrass when the engine is running and such grass is expelled through thechannel 2.

The housing 1 also supports the shaft 40 of a starter assembly, and thisshaft carries a gear 41 and a pulley 42 which can be rotated by acustomary rope (not shown). The starter is of the reversible type, i.e.,by pulling the rope the operator causes the gear 41 to move into meshwith and to rotate a ring gear 43 on the impeller wheel 33 whereby thewheel 33 rotates the crankshaft 29 to start the engine. The vanes 44 ofthe wheel 33 suck air through the filter 50 at the upper side of thehousing 1 and such air flows through the casing 15 below the cylinder 8and into the air circulating compartment 7 where it cools the fins 27.(Hot air is discharged upwardly at the open upper side of thecompartment 7.

The carburetor accommodates a throttle valve 45 and an air flowregulating valve 46. These valves are installed prior to attachment ofcover 18 to the housing 1. A suction pipe 47 extends from the carburetor10 into the bottom portion of the fuel tank 5. An automatic fuel supplyregulator 48 extends into the path of air circulated by the vanes 44 tocontrol the delivery of fuel as a function of the engine speed.

FIG. 2 further shows an ignition coil 49 which is secured to themounting means 16, 17 of the housing 1. The air cleaner or filter 50 isinserted into the space 9 and also extends into the recess 9 when thecover 18 is attached to the housing. This filter is always accessiblefrom above and its plane is preferably parallel to the axis of thecrankshaft 29.

An important advantage of the just described construction is that thelawnmower can be produced at a surprisingly low cost without affectingthe quality. The lawn mower is of compact and lightweight design and itsheight is very low so that it can be readily pushed below bushes,lowermost branches of trees and into other hard-to-reach areas.Furthermore, and since the overall weight of the lawnmower is low, itcan be readily handled in mowing of grass on steeply inclined grounds.Such low weight also insures that the wheels 3 leave minimal traces inthe lawn and renders it possible to entrust the operation of thelawnmower to women and adolescents because its manipulation requires asmall effort. The assembly or dismantling consumes little time becausethe lawnmower comprises a small number of parts. This facilitates repairand periodic inspection or cleaning.

The fact that the cylinder '8 is installed in horizontal positioncontributes to compactness and low weight of the lawnmower. Suchcompactness is further due to placing of the cylinder 8 between the fueltank 5 and the exhaust duct 12, and to the fact that the cylinder -8,crank case 4, tank 5 and exhaust duct 12 occupy a circular space whichis surrounded by the evacuating channel 2. The carburetor 10 is locateddirectly opposite the exhaust duct 12. In order to insure that littleheat is transmitted from the exhaust duct 12 to the crank case 4 andother heat-sensitive parts, the housing 1 is provided with theaforementioned heat-insulating gap or gaps 13 and the impeller wheel 33circulates coolant in areas which are likely to be overheated byexchange of heat with the duct 12. Also, the cross section of suchportions of housing 1 which connect the exhaust duct 12 with adjoiningparts are held to a minimum. The fuel tank 5 is located directly belowthe feed duct 11 so that fuel can be drawn into this duct by flowing ina very short path.

Additional savings in space and cost are achieved by employing theimpeller Wheel 33 as a means for closing and sealing the central portionof the housing from below and by employing the impeller wheel as a meansfor transmitting motion to the piston 32 during starting and as acarrier for the magnet 36. The marginal portion 34 of the impeller wheel33 is shaped during casting of this wheel and the same applies for theadjoining portion of the housing 1 so that the formation of asatisfactory seal 35 requires no separate treatment of parts 1 and 33.The blade 38 can be affixed to the crankshaft 29 and/or to the impellerwheel 33.

The filter 50 is accessible from the exposed upper side of the cover 18and can be inspected or replaced at any time. Also, and since the parts23, 24 are provided in the housing 1, the assembly of my lawnmowermerely requires insertion of valves 45, 46, of a nozzle, of wheels 3, ofcylinder 8, crankshaft 29, wheel 33, blade 38, starter assembly,ignition coil 50 and the fastening of cover 18. Many of those parts ofthe housing 1 which constitute components of the engine aresubstantially normalto the general plane of the housing.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art and, therefore, suchadaptations should and are intended to be comprehended within themeaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

I claim:

1. -A lawnmower comprising a wheel mounted housing consisting of aone-piece metallic casing; rotary blade means; and an internalcombustion engine comprising substantially horizontal cylinder means, arotary output member connected with said blade means and a plurality ofcomponents constituting integral parts of said onepiece housing andincluding a crank case for said output member, carburetor means, a fueltank, and an exhaust duct for combustion products, said cylinder meansbeing removably located in a compartment provided in said housingintermediate said exhaust duct and said fuel tank.

2. A lawnmower as defined in claim 1, wherein said cylinder means islocated intermediate said fuel tank and said exhaust duct, said cylindermeans, exhaust duct, fuel tank and crank case occupy a substantiallycircular central portion of said housing.

3. A lawnmower comprising a wheel-mounted housing consisting of aone-piece metallic casting; rotary blade means; an internal combustionengine having cylinder means, a rotary output member connected to saidblade means and a plurality of components including a crank case forsaid output member, carburetor means, a fuel tank, an exhaust duct forcombustion products, and a compartment housing said cylinder means, saidcomponents constituting integral parts of said one-piece housing andhaving upper open ends; and a single substantially flat cover releasablyconnected to said housing and closing said open ends of said components.

4. A lawnmower as defined in claim 3, wherein said components furtherinclude a casing defining a path for cooling air into said compartment.

5. A lawnmower as defined in claim 4, further comprising a removable aircleaner, said components further including a portion defining anair-admitting space in communication with said path and accommodatingsaid air cleaner. I

'6. A lawnmower as defined in claim 3, wherein said cylinder meansremovably extends into a composite compartment defined by said housingand said cover.

7. A lawnmower as defined in claim 6, wherein said cover resembles aplate having a recess forming part of said composite compartment and webmeans abutting against an adjoining portion of said housing.

8. A lawnmower as defined in claim 3, wherein said housing has anunderside and said output member is r0- tatable about a substantiallyvertical axis, and further comprising an impeller wheel mounted on saidoutput member adjacent to the underside of said housing.

9. A lawnmower as defined in claim 8, wherein said impeller wheel isconnected to said output member directly above said blade means.

10. A lawnmower as defined in claim 8, wherein said output member is acrankshaft.

11. A lawnmower as defined in claim 8, wherein said impeller wheel has amarginal portion forming with said housing an annular labyrinth seal.

12. A lawnmower as defined in claim 3, said cylinder means having asmooth-surfaced portion received in said compartment defined by saidhousing, said smooth-surfaced portion having exhaust port means incommunication with said exhaust duct and fuel admitting port means incommunication with a feed duct provided in said housing between saidcarburetor means and said compartment.

13. A lawnmower as defined in claim 12, wherein said housing has apassage connecting said exhaust port means with said exhaust duct.

14. A lawnmower as defined in claim 12, wherein said cylinder meanscomprises flange means detachably secured to said housing and coolingfins received in a second compartment provided in said housing adjacentto said first mentioned compartment.

References Cited UNITED STATES PATENTS 2,491,630 12/1949 Voorhies123-193 XR 3,044,239 7/1962 Harkness 5625.4

FOREIGN PATENTS 224,514 10/ 1959 Australia.

ROBERT PESHOCK, Primary Examiner I. A. OLIFF, Assistant Examiner

